Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4a099c5cd5b54e2…

MALICIOUS

PDF

81.3 KB Created: 2021-09-19 23:52:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 0ae884e898cbf57b192b02f75b13cf62 SHA-1: 81b215ece876d5030e3c57447c0c80079fe76df2 SHA-256: b4a099c5cd5b54e2b9fda42afba04a49126126e1f2beef65595b986e1b92b5c7
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains numerous embedded URLs, many of which point to compromised CMS upload directories or are hosted on disposable domains, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple external URIs suggests an attempt to lure users to potentially harmful sites. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://laborke.ru/uplcv?utm_term=pokemon+gold+gbc+rom PDF link annotation
    • https://ensegun2.com/ckfinder/userfiles/files/wuxazusegalorikunipurum.pdfIn PDF document text
    • http://e2ingenieros.com/ckfinder/userfiles/files/88901187967.pdfIn PDF document text
    • https://taxforce.nl/userfiles/files/83764395572.pdfIn PDF document text
    • https://adamant54.ru/userfiles/files/96814544299.pdfIn PDF document text
    • http://veterinariomauracotti.it/userfiles/files/nonepefidulotugina.pdfIn PDF document text
    • http://yeditepegumruk.com/userfiles/33805217299.pdfIn PDF document text
    • http://nato-denkmal.de/uploads/file/48599181128.pdfIn PDF document text
    • https://mosoptagro.ru/wp-content/plugins/super-forms/uploads/php/files/1b7d27337a63b63805c28f48bab4b41b/41307175232.pdfIn PDF document text
    • http://hypotekaprezamestnancov.sk/res/file/47098827971.pdfIn PDF document text
    • https://donnasalon.ru/wp-content/plugins/super-forms/uploads/php/files/445faec2d9768d4753f25d59f0e4da57/wezaxepebit.pdfIn PDF document text
    • http://gostium.com/wp-content/plugins/formcraft/file-upload/server/content/files/16147541500fe0---besobumuxapusidolaseg.pdfIn PDF document text
    • http://studiogaleazzo.eu/userfiles/files/13286063227.pdfIn PDF document text
    • https://beta.nhatthiengroup.com/files/uploaded/files/46632755110.pdfIn PDF document text
    • http://smalternatywa.pl/media/upload/files/c3a0bc8f45943248148c17ea626390a9.pdfIn PDF document text
    • http://assytekservizi.com/userfiles/files/bozutalenasa.pdfIn PDF document text
    • https://immsac.pe/sgi_userfiles/userfiles/files/3188705913.pdfIn PDF document text
    • http://www.ibadirect.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139de4f5bb8f---18815931723.pdfIn PDF document text
    • https://jin-hung.com/userfiles/file/nizafolikivoxi.pdfIn PDF document text
    • http://defhjdr.friend-match.com/upload/files/8981404048.pdfIn PDF document text
    • https://360clothing.in/home/www360cl/public_html/uploads/images/files/64895872049.pdfIn PDF document text
    • http://pietroquatriniarchitetto.eu/userfiles/files/73389011758.pdfIn PDF document text
    • https://infypos.com/infyposcms/media/19790077661.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d847.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD847 10428 bytes
SHA-256: 1efa0b464c7c3e1894909ef6021cc83c4d9b26c7a33b9e8b1bae621a7e4adfd3
font_01_sfnt_off0000ef9b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF9B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000107ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107AD 17956 bytes
SHA-256: 0a795d8b9a67c767a928ccf1817eec9533460a3cc9fb67d602fe8a895ee93ae5